腔高对压电液压驱动器性能的影响

Influence of Pump-Chamber Height on Performance of Piezohydraulic Actuator

为满足大行程、高输出力精密驱动及振动控制的需求,设计了压电叠堆隔膜泵驱动的压电液压驱动器并进行了试验.利用实际液体可压缩的特性,建立了压电液压驱动器理论分析模型,分析了液体体积模量以及压电泵腔高对其输出性能的影响规律.结果表明,其他结构参数确定时压电液压驱动器输出能力随液体体积模量的减小而降低,并存在最佳腔高使其输出能力最大.利用尺寸为4 mm×4 mm×80 mm的压电叠堆制作了泵腔直径30 mm、高度分别为0.3 mm、0.6 mm、0.8 mm、1.0 mm、1.3 mm的压电泵,用于驱动尺寸为20×100 mm3的液压缸.以水为工作介质,在电压150 V、频率60～400 Hz条件下测试了驱动器的输出速度及驱动力.工作频率为300 Hz时,腔高0.6 mm(最佳值)时的输出速度为13.2 mm/s,分别为腔高0.3 mm和1.3 mm时的1.1倍和2.28倍;工作频率为80Hz时,腔高0.3 mm(最小腔高)时的驱动力为105 N,是腔高1.3 mm时驱动力的2.3倍,说明选取合理的泵腔高度可有效提高驱动器的输出性能.

To meet the need of accuracy actuation and vibration control for large force and long displacement, a piezohydraulic actuator driven by pieostack pump was designed and tested. Based on the compressibility of actual liquid, an analytical model of the piezohydraulic actuator was established, and the influence of liquid bulk modulus and pump-chamber height on its performance was analyzed. The analytical results show that, the output performance of the piezohydraulic actuator decreases with the reducing of liquid bulk modulus under given structural parameters, and there is an optimal chamber height for the piezohydraulic actuator to obtain maximal output capability. Using a piezostack measured 4 mm× 4 mm × 80 mm, pieozstack pumps with chamber diameter of 30 mm and chamber height of 0. 3 mm,0. 6 mm,0. 8 mm, 1.0 mm, 1.3 mm were fabricated to drive a hydraulic cylinder measured 20 × 100 mm^3. At voltage of 150 V and frequency range from 60 Hz to 400 Hz, the piezohydraulic actuators were tested with water as liquid medium. At frequency of 300 Hz, the achieved maximal velocity of piezohydraulic actuator with chamber height of 0. 6mm （the optimal one） is 13.2 mm/s, which is 1.1 times and 2. 28 times of those with chamber height of 0. 3 mm and 1.3 mm, respectively. At frequency of 80 Hz, the obtained maximal driving force with chamber height of 0. 3 mm （the minimal chamber height） is 105 N, which is 2.3 times of that with chamber height of 1.3 mm. The experimental results show that both the output velocity and driving force can be enhanced with reasonable design of chamber height.